JP4329133B2 - Camera apparatus with camera shake correction function and camera shake correction method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention captures a video camera, a still camera, and other moving images or still images with a camera shake correction function using optical correction means using a mechanical mechanism such as a shift method as correction means for correcting image blur. Relates to the device.
[0002]
[Prior art]
As a camera shake correction system for a video camera, there is an apparatus using an optical correction means called a “VAP method” in which a vari-angle prism is tilted in accordance with a camera shake amount as a correction means for correcting image blur.
[0003]
In addition, as a camera shake correction system for video cameras, this correction means uses an optical correction means called a “shift method” that has been used in conventional single-lens reflex cameras to move a shift lens in accordance with the amount of camera shake. Also exist.
[0004]
In the case of the VAP optical correction means, since there are few mechanical contact points in the mechanism of the vari-angle prism, noise is hardly generated when the vari-angle prism is driven. Therefore, in a video camera with a camera shake correction function using a VAP optical correction means, it is not necessary to make a device for suppressing such noise in the camera shake correction control, and no device for that purpose has been made.
[0005]
Similarly, even a video camera with a camera shake correction function using a shift type optical correction means has not been devised in the past to suppress noise when driving a shift lens.
[0006]
[Problems to be solved by the invention]
However, in the shift type optical correction means, as compared with the VAP type optical correction means, there are many mechanical contact points due to pins or the like in the mechanism that supports the shift lens in a movable manner. Noise is likely to occur when driving.
[0007]
As a result, in a conventional video camera with a camera shake correction function using a shift type optical correction means, noise due to the optical correction means is generated at the time of camera shake correction, particularly when correcting a large amplitude camera shake. There was a problem that would become larger.
[0008]
The present invention has been made in view of the above points, and is a video camera, a still camera, a digital still camera, other moving images with a camera shake correction function using an optical correction means using a mechanical mechanism including a shift method, A still image capturing apparatus is provided that suppresses noise caused by optical correction means during camera shake correction.
[0009]
[Means for Solving the Problems]
The imaging device according to the present invention, as described in claim 1, performs detection for detecting a camera shake amount of the imaging device, and integration calculation for obtaining a camera shake signal from the detection result of the detection unit. the calculating means for calculating the necessary information from the output value for the correction of image blur,-out based on the calculation result of the calculating means, the temporal change in driven by the corresponding image of the output value of the integration operation In the photographing apparatus with a camera shake correction function having a correction unit that corrects the shake, the calculation unit is configured to output an output value of the integral calculation from a first boundary value that is smaller than a predetermined limiter value indicating the end of the correction range. the large range, the output value of the integration operation while decreasing the feedback coefficient in the integral calculation closer to this limit value, the second boundary before the output value of the integration operation reaches this limit value From, by increasing the reduction rate of the feedback coefficient in the integral calculation, as compared with the case where the reduction rate of the feedback factor is constant in a range larger than the first boundary value, the output value of the integral calculation is this The change point from the state not restricted by the limiter value to the restricted state and the output value of the integral operation from the state restricted to this limiter value to the state of change from the restricted state to the time change of the output value of the integral operation It is characterized by smoothness .
According to the camera shake correction method of the present invention, as described in claim 3, the detection means for detecting the camera shake amount of the photographing apparatus, and the integration calculation for obtaining the camera shake signal from the detection result of the detection means, calculating means for calculating the necessary information from the output value of the integral calculation for the correction of image blur,-out based on the calculation result of the calculating means is driven in response to the temporal change in the output value of the integration operation In a camera shake correction method in a photographing apparatus with a camera shake correction function having a correction means for correcting image blur, the calculation means has a first output value of the integral calculation smaller than a predetermined limiter value indicating the end of the correction range . the greater range than one boundary value, the steps of the output value of the integral calculation reduces the feedback coefficient in the integral calculation closer to this limit value, the calculating means, the integral From the second boundary value before the output value of the calculation reaches this limit value in the first range greater than the boundary value, by increasing the reduction rate of the feedback coefficient in the integral calculation, the first boundary value Compared with the case where the rate of decrease of the feedback coefficient is constant over a larger range, the change point from the state where the output value of the integral operation is not limited to the limiter value to the state where the output value of the integral operation is restricted and the output value of the integral operation are And a step of smoothing a temporal change in the output value of the integral operation at the change point from the state restricted to the limiter value to the state not restricted .
[0010]
According to the photographing apparatus and the camera shake correction method, the calculation means for performing the integration calculation for obtaining the camera shake signal from the detection result of the camera shake amount has an output value of the integration calculation greater than a predetermined limiter value indicating the end of the correction range. small in a range larger than the first boundary value, the output value of the integration operation while decreasing the feedback coefficient in the integral operation closer to the limit value, before the second output value of the integral calculation reaches this limit value By increasing the rate of decrease of the feedback coefficient in the integral operation from the boundary value, the output value of the integral operation is smaller than when the rate of decrease of the feedback coefficient is constant in a range larger than the first boundary value. The product of the change point from the state not restricted by the limiter value to the restricted state and the output value of the integration operation from the state restricted to the limiter value to the state not restricted. To smooth the temporal change in the output value of the calculation. Then, information necessary for image blur correction is calculated by the calculation means from the output value of the integration calculation, and the correction means responds to the temporal change of the output value of the integration calculation based on the calculation result of the calculation means. To correct the image blur.
[0011]
In this way, the time of the output value of the integral operation at the change point from the state where the output value of the integral operation is not limited to the limiter value to the state where it is restricted and the change point from the state limited to the limiter value to the state where it is not restricted By smoothing the change, it becomes difficult to suddenly stop from the state where the correction means is driven or to start driving suddenly from the stopped state, and stop or stop from the driven state. Even when driving is started from the state of being stopped, the driving is gently stopped or the driving is started. Accordingly , even when an optical correction unit using a mechanical mechanism such as a shift method is used as the correction unit, noise caused by the optical correction unit during camera shake correction is suppressed.
[0012]
In an imaging apparatus using an angular velocity sensor as the detection means, as an example, the calculation means performs an integral calculation for obtaining an angular displacement signal of camera shake from the output of the angular velocity sensor as described in claim 2, and this integration the range output value is larger than the first boundary value operation, the output value of the integration operation while decreasing the feedback coefficient in the integral operation closer to the limit value, from the second boundary value, the By increasing the rate of decrease of the feedback coefficient in the integral calculation, the output value of the integral operation is compared with the case where the rate of decrease of the feedback coefficient is made constant in a range larger than the first boundary value. The change point from the state not restricted by the value to the restricted state and the change point from the state in which the output value of the integral calculation is restricted to the limiter value to the state not restricted. It is preferable that one that smoothes the temporal variation of the output value of the serial integral calculation.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Next, an example in which the present invention is applied to a video camera will be described.
FIG. 1 is a block diagram showing the overall configuration of a camera shake correction system for a video camera to which the present invention is applied. The camera shake correction system includes an angular velocity sensor 11, an amplifier unit 12, an A / D converter 13, a microcomputer 21, a servo circuit 31, and a lens unit 41. The lens unit 41 includes a shift unit 42. .
[0014]
The angular velocity sensor 11 detects a camera shake amount of the video camera as an angular velocity Sgyro. The angular velocity sensor 11 uses two angular velocity sensors for detecting the amount of camera shake in the vertical direction and the horizontal direction. Accordingly, there are two types of angular velocity detected by the angular velocity sensor 11 in the vertical direction and the horizontal direction. However, here, these two systems are collectively expressed as an angular velocity Sgyro, and the subsequent signal flow is also expressed as one symbol by combining the two systems in the vertical direction and the horizontal direction.
[0015]
The angular velocity Sgyro is amplified by the amplifier unit 12 and sent to the A / D converter 13 as a signal Samp. The A / D converter 13 samples the signal Samp and sends it to the microcomputer 21 as an angular velocity sampling value Ssamp.
[0016]
The microcomputer 21 calculates the shift lens target position Sdst necessary for the optimum camera shake correction according to the zoom position based on the angular velocity sampling value Ssamp and the lens focal length f sent from the lens unit 41.
[0017]
The servo circuit 31 sends a drive voltage Sdrive having a level corresponding to the difference between the shift lens target position Sdst sent from the microcomputer 21 and the shift lens position Spsd sent from the shift unit 42 to the shift unit 42. As a result, as will be described later, the shift lens in the shift unit 42 moves to the target position Sdst, and camera shake correction is realized.
[0018]
FIG. 2 is a functional block diagram showing processing performed by the microcomputer 21. The angular velocity sampling value Ssamp has its low-frequency component cut by the high-pass filter 22 and is sent to the integration filter 23 as a signal Shpf. The integration filter 23 integrates the signal Shpf to obtain an angular displacement signal Sint of camera shake. The gain adjusting unit 24 calculates the shift lens target position Sdst from the angular displacement signal Sint and the lens focal length f.
[0019]
FIG. 3 is a diagram illustrating a configuration of the shift unit 42. In the housing of the shift unit 42, a shift lens 43 is supported by a mechanical mechanism such as a pin (not shown) so as to be movable in the vertical and horizontal directions. When the vertical drive voltage Sdrive_v of the drive voltage Sdrive in FIG. 1 is applied to the vertical drive coil 51, the shift lens 43 is driven in the vertical direction to move. When the horizontal drive voltage Sdrive_h of the drive voltage Sdrive is applied to the horizontal drive coil 61, the shift lens 43 is driven and moved in the horizontal direction.
[0020]
The position of the shift lens 43 in the vertical direction is detected as follows. An IRED (infrared light emitting diode) 52 and a PSD (photodetector having a light receiving portion arranged one-dimensionally in the vertical direction) 53 are fixed to the housing side of the shift unit 42, and a slit (not shown) is formed in the shift lens 43. It is possible to move together with the shift lens 43 by being fixed to the side. Infrared light emitted from the IRED 52 is irradiated to the light receiving portion of the PSD 53 through this slit. When the vertical position of the shift lens 43 is changed, the vertical position of the slit is also changed, so that the irradiation position of the infrared light on the light receiving portion of the PSD 53 is changed.
[0021]
The vertical position detection circuit 54 drives the IRED 52 and the PSD 53, and generates the shift lens vertical position Spsd_v according to the irradiation position of the infrared light on the light receiving portion of the PSD 53. Thereby, the vertical position of the shift lens 43 is detected as the shift lens vertical position Spsd_v.
[0022]
Similarly, the horizontal position of the shift lens 43 is also determined by the IRED 62, the slit, the PSD 63 (a photodetector having a light receiving portion arranged one-dimensionally in the horizontal direction) and the horizontal position detection circuit 64, and the shift lens horizontal position Spsd_h. Detected as
[0023]
4 to 6 are diagrams illustrating the principle of camera shake correction by the shift method. FIG. 4 shows a state where there is no camera shake. In this state, no image blur occurs on the CCD 1.
[0024]
FIG. 5 shows a state in which camera shake occurs and camera shake correction is not performed. In this state, the light flux from the subject is displaced relative to the optical axes of the lenses 43, 44, and 45 in the lens unit 41, thereby causing image blur on the CCD 1.
[0025]
FIG. 6 shows a state in which camera shake has occurred and camera shake correction has been performed. In this state, by moving the shift lens 43 to deflect the light beam, the relative displacement between the light beam and the lens optical axis due to camera shake is cancelled. As a result, the position of the light beam on the CCD 1 is maintained at the same position as that in FIG. 4 where there is no camera shake, thereby realizing camera shake correction.
[0026]
FIG. 7 is a functional block diagram showing processing of the integration filter 23 of FIG. The input signal Shpf at each sampling timing is delayed by one sampling period by the delay element 71, multiplied by the feedback coefficient k (k <1) by the multiplier 72, and input by the adder 73 at the immediately subsequent sampling timing. It is added to the signal Shpf. In this way, the input Shpf at each sampling timing is accumulated, and is output as a camera shake angular displacement signal Sint via the limiter 74.
[0027]
Since the input Shpf has positive and negative signs according to the direction of camera shake (up or down in the vertical direction or right or left in the horizontal direction), the output Sint also has positive and negative signs. The limiter 74 limits the output Sint so that it does not exceed the positive upper limit value or the negative lower limit value (limiter value).
[0028]
The feedback coefficient k is not a constant value but changes according to the absolute value | Sint | of the output Sint. Before showing the relationship between | Sint | and k in camera shake control according to the present invention, FIG. 8 shows the relationship between | Sint | and k in conventional camera shake control. With a certain value (a value sufficiently smaller than the limiter value) as a boundary, k is a constant value in a range where | Sint | is less than or equal to the boundary value, and in a range where | Sint | is larger than the boundary value, | Sint | As k increases, k decreases at a constant decrease rate.
[0029]
Such a boundary is provided because the relationship between the input Shpf and the output Sint is linear when | Sint | is sufficiently smaller than the limiter value because the absolute value of the input Shpf is small (that is, the amount of camera shake is small). Therefore, in the case where | Sint | reaches the limiter value because the absolute value of the input Shpf is large (that is, the amount of camera shake is large), | Sint | is the limiter value. The camera shake is corrected well within the correction range until the value reaches the limit, but the camera shake correction suddenly stops at the moment when | Sint | reaches the limiter value (the end of the correction range). This is to reduce the “feel”.
[0030]
In the conventional camera shake control shown in FIG. 8, a device for reducing the feeling of hitting the end of the correction range is made in this way, but a device for suppressing noise by the shift unit 42 at the time of camera shake correction is not made at all. Absent. This will be described with reference to the timing chart of FIG. 10 showing an example of the temporal change of the output Sint in the conventional camera shake control.
[0031]
At time t1, the output Sint reaches the limiter value due to an increase in the absolute value of the input Shpf (an increase in the amount of camera shake), so that the output Sint is limited to the limiter value. Thereafter, at time t2, the absolute value of the output Sint falls below the limiter value due to the decrease in the absolute value of the input Shpf (decrease in the amount of camera shake), so that the output Sint returns to a state where it is not limited to the limiter value. After that, at time t3, the output Sint is again limited to the limiter value, and at time t4, the output Sint is returned to the state not limited to the limiter value.
[0032]
In this case, a change point from a state that is not limited to the limiter value such as time t1 or t3 to a state that is restricted, or a change from a state that is limited to the limiter value such as time t2 or t4 to a state that is not restricted. On the point, the temporal change of the output Sint is not smooth but steep. Since the movement of the shift lens 43 corresponds to the temporal change of the output Sint, it stops suddenly from the moving state at time t1 or t3 in FIG. 10, and stops at time t2 or t4. Suddenly start moving. At such a moment, noise easily occurs from the shift unit 42 having many mechanical contact points in the mechanism.
[0033]
FIG. 9 is a diagram showing the relationship between | Sint | and k in the camera shake control according to the present invention as compared with FIG. As shown in FIG. 8, instead of decreasing k at a constant reduction rate in a range where | Sint | is larger than the boundary value, in a range where | Sint | exceeds a limit value a times (0 <a <1), The decrease rate of k with respect to the increase of | Sint | is increased.
[0034]
Therefore, in the case of the present invention, in the range where | Sint | is less than a times the limiter value, the increase ratio of | Sint | with respect to the increase in the absolute value of the input Shpf is equal to the conventional case, but | Sint | In the range where the value exceeds a times the limit value (that is, the range where | Sint | approaches the limiter value), the rate of increase of | Sint | with respect to the increase in the absolute value of the input Shpf is smaller than in the conventional case.
[0035]
FIG. 11 is a timing chart showing the temporal change of the output Sint in the camera shake control according to the present invention as compared with FIG. In the range in which | Sint | exceeds a times the limiter value, as an effect that the increase rate of | Sint | is small, the output Sint does not reach the limiter value during the period from time t1 to t2. The time change of the output Sint during this period is smooth, and the time change of the output Sint does not occur during the period from time t3 to t4 as compared with the case of FIG. 10 although the output Sint reaches the limiter value. It is smooth.
[0036]
Therefore, it becomes difficult to suddenly stop from the state where the shift lens 43 is moving or to start moving suddenly from the stopped state, and from the moving state to the stopped or stopped state. When starting, it will stop gently or start moving. Thereby, the noise by the shift unit 42 at the time of camera shake correction comes to be suppressed.
[0037]
In the above example, by increasing the decrease rate of k with respect to the increase of | Sint | in the range where | Sint | exceeds a times the limiter value, | Sint with respect to the increase in the absolute value of the input Shpf in this range. The rate of increase of | is reduced. However, as another example, while the reduction rate of k remains the same as that in the conventional camera shake control illustrated in FIG. 8, the limiter 74 in FIG. 7 is used to increase the absolute value of the input Shpf in this range. Decreasing the rate of increase of the absolute value of the output Sint (that is, the limiter 74 does not output the input value as it is until the input value reaches the threshold for limiting the output value as in the conventional case, but the input value The absolute value of the output may be made smaller than the input before reaching the threshold value).
[0038]
In the above example, specific information that suppresses noise by the shift unit during camera shake correction is calculated in the process of integration for obtaining the angular displacement signal of camera shake from the output of the angular velocity sensor. In a video camera that uses an angular velocity sensor or other appropriate sensor (for example, an acceleration sensor) as the detection means, the specific information may be calculated in an appropriate calculation process other than the integral calculation.
[0039]
In the above example, the present invention is applied to a video camera using a shift type optical correction unit. However, a video camera using an optical correction unit other than the shift type (particularly, a mechanical mechanism). The present invention may also be applied to.
[0040]
In the above example, the present invention is applied to a video camera. However, the present invention may be applied to a still camera other than the video camera, a digital still camera, and other moving image or still image photographing apparatuses.
Further, the present invention is not limited to the above-described embodiments, and various other configurations can be taken without departing from the gist of the present invention.
[0041]
【The invention's effect】
As described above, according to the photographing apparatus with a camera shake correction function and the camera shake correction method according to the present invention, the correction unit that corrects the image blur suddenly stops from the driven state or from the stopped state. Suddenly starting to drive is less likely to occur, and when stopping from a driven state or starting from a stopped state, it will stop gently or start driving, so correction Even when an optical correction means using a mechanical mechanism such as a shift method is used as the means, noise caused by the optical correction means during camera shake correction can be suppressed.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an overall configuration of a camera shake correction system of a video camera to which the present invention is applied.
FIG. 2 is a functional block diagram illustrating an example of processing performed by the microcomputer 21 of FIG.
3 is a diagram showing a configuration of a shift unit 42. FIG.
FIG. 4 is a diagram illustrating the principle of camera shake correction by a shift method.
FIG. 5 is a diagram illustrating the principle of camera shake correction by a shift method.
FIG. 6 is a diagram illustrating the principle of camera shake correction by a shift method.
FIG. 7 is a functional block diagram showing processing in the integration filter.
FIG. 8 is a diagram illustrating a relationship between | Sint | and k in conventional camera shake control.
FIG. 9 is a diagram illustrating a relationship between | Sint | and k in camera shake control according to the present invention.
FIG. 10 is a timing chart showing an example of a temporal change in output Sint in conventional camera shake control.
FIG. 11 is a timing chart showing an example of a temporal change in output Sint in camera shake control according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... CCD, 11 ... Angular velocity sensor, 12 ... Amplifier part, 13 ... A / D converter, 21 ... Microcomputer, 22 ... High-pass filter, 23 ... Integration filter, 24 ... Gain adjustment , 31 ... Servo circuit, 41 ... Lens unit, 42 ... Shift unit, 43 ... Shift lens, 51 ... Vertical drive coil, 52, 62 ... IRED, 53, 63 ... PSD, 54 ... ... vertical position detection circuit, 61 ... horizontal drive coil, 64 ... horizontal position detection circuit

Claims (3)

Detection means for detecting the amount of camera shake of the imaging device;
An arithmetic operation for obtaining a camera shake signal from the detection result of the detection means, and calculating means for calculating information necessary for correcting image blur from the output value of the integration operation;
-Out based on the calculation results of the calculating means, the image stabilizer function imaging device having a correcting means for correcting the blur of the integral calculation of the output value of the temporal change in the correspondingly driven by the image,
As the computing means, the output value of the integral calculation is in a range larger than the first boundary value smaller than a predetermined limiting value indicating the end of the correction range, the output value of the integral calculation approaches the limit value while decreasing the feedback coefficient in the integrating calculation, from the second boundary value before the output value of the integral calculation reaches the limit value, by increasing the reduction rate of the feedback coefficient in the integrating calculation, the first Compared with the case where the rate of decrease of the feedback coefficient is constant in a range larger than the boundary value of the above, the change point from the state where the output value of the integration calculation is not limited to the limiter value and the state where the integration is limited shake correction function imaging instrumentation which the output value of the operation to smooth the temporal change of the output value of the integration operation in the changing point to state that is not limited from the restricted state to the limiter value . In the imaging device with a camera shake correction function according to claim 1,
An angular velocity sensor is used as the detection means,
The arithmetic unit performs the integral operation for obtaining the angular displacement signal of the shake hand from the output of the angular velocity sensor, in the range output value of the integration calculation is larger than the first boundary value, the output value of said integral calculation together but it reduces the feedback coefficient in the integrating operation closer to the limit value, from said second boundary value, by increasing the reduction rate of the feedback coefficient in the integrating calculation, larger than the first boundary value Compared with the case where the rate of decrease of the feedback coefficient is constant in the range, the change point from the state where the output value of the integral operation is not limited to the limiter value and the output value of the integral operation are An imaging apparatus with a camera shake correction function that smoothes a temporal change in an output value of the integration operation at a change point from a state limited to a limiter value to a state not limited . Detection means for detecting the amount of camera shake of the imaging device;
An arithmetic operation for obtaining a camera shake signal from the detection result of the detection means, and calculating means for calculating information necessary for correcting image blur from the output value of the integration operation;
-Out based on the calculation results of the calculating means, the image stabilization method in image stabilizer function imaging device having a correcting means for the integration operation of the driven corresponding to the temporal change of the output value to correct the image blur ,
As the arithmetic unit, the output value of the integral calculation is in a range larger than the first boundary value smaller than a predetermined limiting value indicating the end of the correction range, the output value of the integral calculation approaches the limit value Reducing the feedback coefficient in the integral operation;
It said calculating means, from the second boundary value before the output value of the integral calculation reaches the limit value in the range larger than the first boundary value, increasing the reduction rate of the feedback coefficient in the integrating operation Thus, compared to the case where the rate of decrease of the feedback coefficient is constant in a range larger than the first boundary value, the output value of the integration operation is changed from a state where the output value is not limited to the limiter value. Smoothing a temporal change of the output value of the integration operation at a change point and a change point from the state where the output value of the integration operation is limited to the state where the output value of the integration operation is not limited to the limiter value. .

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